For FY09, we have used multi-dimensional NMR and site-directed mutagenesis methods to assign the chemical shifts of methyl groups of Val, Leu, and Ile of histones in the nucleosome, which will be used as probes for studying the dynamics of nucleosome and its interactions with other proteins such as linker histone H1 and high mobility groups. We have also investigated the structure of Scm3 complexed with centromere histone variant Cse4 and histone H4. Our studies are important for understanding how DNAs are separated during cell division and provide insights on how mis-separation of DNAs may cause human diseases.